Tag Archives: Physics

Like many physicists, Michio Kaku thinks our universe will end in a “big freeze.” However, unlike many physicists, he thinks we might be able to avoid this fate by slipping into a parallel universe.”

One of the most fascinating discoveries of our new century may be imminent if the Large Hadron Collider outside Geneva produces nano-blackholes when it goes live again. According to the best current physics, such nano blackholes could not be produced with the energy levels the LHC can generate, but could only come into being if a parallel universe were providing extra gravitational input. Versions of multiverse theory suggest that there is at least one other universe very close to our own, perhaps only a millimeter away. This makes it possible that some of the effects, especially gravity, “leak through,” which could be responsible for the production of dark energy and dark matter that make up 96% of the universe.

“The multiverse is no longer a model, it is a consequence of our models,” says Aurelien Barrau, particle physicist at CERN.

While it hasn’t been proven yet, many highly respected and credible scientists are now saying there’s reason to believe that parallel dimensions could very well be more than figments of our imaginations.

“The idea of multiple universes is more than a fantastic invention—it appears naturally within several scientific theories, and deserves to be taken seriously,” stated Aurelien Barrau, a French particle physicist at the European Organization for Nuclear Research (CERN).

There are a variety of competing theories based on the idea of parallel universes, but the most basic idea is that if the universe is infinite, then everything that could possibly occur has happened, is happening, or will happen.

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This problem is captured in the famous thought experiment of Schrödinger’s cat. This unhappy feline is inside a sealed box containing a vial of poison that will break open when a radioactive atom decays. Being a quantum object, the atom exists in a superposition of states – so it has both decayed and not decayed at the same time. This implies that the vial must be in a superposition of states too – both broken and unbroken. And if that’s the case, then the cat must be both dead and alive as well.

To explain why we never seem to see cats that are both dead and alive, and yet can detect atoms in a superposition of states, physicists have in recent years replaced the idea of superpositions collapsing with the idea that quantum objects inevitably interact with their environment, allowing information about possible superpositions to leak away and become inaccessible to the observer. All that is left is the information about a single state.

Physicists call this process “decoherence”. If you can prevent it – by tracking all the information about all possible states – you can preserve the superposition.

In the case of something as large as a cat, that may be possible in Schrödinger’s theoretical sealed box. But in the real world, it is very difficult to achieve. So everyday cats decohere rapidly, leaving behind the single state that we observe. By contrast, small things like photons and electrons are more easily isolated from their environment, so they can be preserved in a superposition for longer: that’s how we detect these strange states.

The puzzle is how decoherence might work on the scale of the entire universe: it too must exist in a superposition of states until some of the information it contains leaks out, leaving the single state that we see, but in conventional formulations of the universe, there is nothing else for it to leak into.

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“The idea of consciousness as a “show” is ultimately derived from the bankrupt representational theory of the mind – a notion that things are present to us by virtue of being “represented” or “modelled” in the brain. You cannot get to representation, however, without prior (conscious, first-order) presentation, so the latter cannot explain the former. Neuroscientists of consciousness try to elude this obvious objection by asserting that representations are not (necessarily) conscious. In fact, all sorts of aspects of consciousness are not conscious after all.

According to Nicholas Humphrey, “before consciousness ever arose, animals were engaged in some kind of inner monitoring of their own responses to sensory stimulation”. What is “inner” about unconscious processes, material events in the material brain? And how can they amount to monitoring? These questions are not silenced by the author’s reassurance that consciousness is “the product of some kind of illusion chamber, a charade”. Nor does Humphrey tell us how he awoke from his consciousness to discover that it is an illusion.”


There is a 50 per cent chance that time will end within the next 3.7 billion years, according to a new model of the universe. A team of physicists led by Raphael Bousso at the University of California, Berkeley rebel against this idea. They say an infinitely expanding universe is contrary to the laws of physics do not work in an infinite cosmos. For these laws to make any sense, the universe must come to an end

There Their argument is simple yet surprisingly powerful: If the universe lasts forever, then any event that can happen, will happen, no matter how unlikely. In fact, this event will happen an infinite number of times, which leads to the key obstacle: When there are an infinite number of instances of every possible observation, it becomes impossible to determine the probabilities of any of these events occurring. And when that happens, the laws of physics simply don’t apply. They just break down. “This is known as the “measure problem” of eternal inflation,” say Bousso and buddies. In short, the laws of physics abhor an eternal universe.

There The only way out of this logic trap is to introduce some kind of catastrophe x factor that brings an end to the universe. Then all the probabilities make sense again and the laws of physics regain their power. “Time is unlikely to end in our lifetime, but there is a 50% chance that time will end within the next 3.7 billion years,” Bousso says.

There The imminent end of time is unnerving but the argument depends crucially on an important assumption about the laws of physics: that we ought to be able to understand why they work, not just observe that they do work. And that’s a philosophical point of view rather than a physical argument. Buosso raises some interesting questions, says the MIT Technology Review, “but nothing to lose any sleep over. At least, not for another 3.7 billion years.”


According to developmental psychologists, three types of knowledge determine a child’s understanding of the world: intuitive physics, intuitive psychology, and with certain reservations, intuitive biology. Part of this knowledge is characterized as core knowledge, that is, knowledge that children learn without instruction; for example, intuitive comprehension of physical, biological, and psychological entities as well as different forms of processes in which these entities engage. Core knowledge — developed by preschool age — provides the foundation for further development. It is based on what psychologists call domain specialized learning mechanisms, or modules, which evolved in response to our Paleolithic environment.

Developmental studies show that core knowledge of physical entities includes the understanding that the world is composed of material objects which have volume and an independent existence in space. Core knowledge of biological entities represents a species-typical adaptation to the problem of food selection and illness avoidance. Even if cultures lack a scientific understanding of disease transmission they still possess an intuitive understanding of it through their core knowledge. Similarly, 4-year-olds know that abnormal behaviors are not contagious, and they can discriminate between contaminated and safe substances despite a lack of visible evidence. Core knowledge of psychological entities includes the understanding that animate beings are intentional agents which have a mind. By the middle of the second year children understand that animate beings can reciprocate actions and have a capacity to move and initiate actions without external force. In addition, small children understand that the contents of mind — thoughts, beliefs, desires, and symbols — are nonmaterial and mental, and that they do not contain the properties they stand for.

17th-century British scientist Robert Boyle was many things: the father of modern chemistry, a founding member of the Royal Society, an inventor, the discoverer of the eponymous gas law, an alchemist, an experimenter on his own body fluids, and a friend to necromancers who offered him sex with demons. Now we can add “clairvoyant” to that colourful list.

Last week the Royal Society displayed for the first time a remarkable document: Boyle’s 24-point wish list for the future of science.

The list, which dates back to the 1660s, was found among his private papers and predicts the inventions of GPS navigation, flight, organ transplants, commercial agriculture and hair dye, among other things.

We were inspired and began to wonder, what could the next 400 years hold? So we asked several of today’s prominent scientists to emulate Boyle and write their own wish lists.

David Eagleman, neuroscientist and fiction writer

  • Download consciousness into a computer to live forever;
  • Travel to extra-solar planets in a reasonable amount of time;
  • Determine how to get by on zero sleep.

Steve Jones, geneticist

  • Understand the science of human emotions broadly enough to put an end to war;
  • A universal abandonment of religious belief as science triumphs over myth;
  • A healthy old age followed by an instant death;
  • The end of the need for grief;
  • The ability to grow fingers as well as we can fingernails;
  • An insight into why snails vary so much genetically from place to place.

Sean Carroll, physicist

  • Understand dark matter and dark energy, which together comprise 96 per cent of our universe;
  • Understand consciousness and intelligence, so that we could mimic it in computers.

Seth Shostak, SETI astronomer.

  • Discover not only abundant biology throughout the cosmos, but at least one instance of extraterrestrial intelligence within the next 100 years;
  • Invent regenerative therapies to cure problems related to aging such as hearing and vision loss and the degeneration of skin tone;
  • A population ten times that of Earth now living in orbiting space colonies within 200 years;
  • The ability to control local climate and alter Earth’s topography.

Jim Al-Khalili, physicist and broadcaster.

  • The convergence of nanoscience and biology enabling nano-robotic surgery and drug delivery to specific locations within cells in the body;
  • Learn whether string theory really lives up to its promise of being a “theory of everything”;.
    The realisation of a true quantum computer;
  • Crack the mystery of life itself: discover how something so unlikely could have emerged by chance on Earth three and a half billion years ago.

Lastly, here are a few of Boyle’s original suggestions: some have come true, while some we’re still holding our breath for:

  • The Prolongation of Life;
  • The Recovery of Youth, or at least some of the Marks of it, as new Teeth, new Hair colour’d as in youth;
  • The Art of Continuing long under water, and exercising functions freely there;
  • The Cure of Wounds at a Distance;
  • The Cure of Diseases at a distance or at least by Transplantation;
  • The Attaining Gigantick Dimensions;
  • The Emulating of Fish without Engines by Custome and Education only;
  • The Acceleration of the Production of things out of Seed;
  • Freedom from Necessity of much Sleeping exemplify’d by the Operations of Tea and what happens in Mad-Men.

Not to mention the question of which way it goes…

by Tim Folger
No one keeps track of time better than Ferenc Krausz. In his lab at the Max Planck Institute of Quantum Optics in Garching, Germany, he has clocked the shortest time intervals ever observed. Krausz uses ultraviolet laser pulses to track the absurdly brief quantum leaps of electrons within atoms. The events he probes last for about 100 attoseconds, or 100 quintillionths of a second. For a little perspective, 100 attoseconds is to one second as a second is to 300 million years.

But even Krausz works far from the frontier of time. There is a temporal realm called the Planck scale, where even attoseconds drag by like eons. It marks the edge of known physics, a region where distances and intervals are so short that the very concepts of time and space start to break down. Planck time—the smallest unit of time that has any physical meaning—is 10-43 second, less than a trillionth of a trillionth of an attosecond. Beyond that? Tempus incognito. At least for now.

Efforts to understand time below the Planck scale have led to an exceedingly strange juncture in physics. The problem, in brief, is that time may not exist at the most fundamental level of physical reality. If so, then what is time? And why is it so obviously and tyrannically omnipresent in our own experience? “The meaning of time has become terribly problematic in contemporary physics,” says Simon Saunders, a philosopher of physics at the University of Oxford. “The situation is so uncomfortable that by far the best thing to do is declare oneself an agnostic.”

The trouble with time started a century ago, when Einstein’s special and general theories of relativity demolished the idea of time as a universal constant. One consequence is that the past, present, and future are not absolutes. Einstein’s theories also opened a rift in physics because the rules of general relativity (which describe gravity and the large-scale structure of the cosmos) seem incompatible with those of quantum physics (which govern the realm of the tiny). Some four decades ago, the renowned physicist John Wheeler, then at Princeton, and the late Bryce DeWitt, then at the University of North Carolina, developed an extraordinary equation that provides a possible framework for unifying relativity and quantum mechanics. But the Wheeler-­DeWitt equation has always been controversial, in part because it adds yet another, even more baffling twist to our understanding of time.

“One finds that time just disappears from the Wheeler-DeWitt equation,” says Carlo Rovelli, a physicist at the University of the Mediterranean in Marseille, France. “It is an issue that many theorists have puzzled about. It may be that the best way to think about quantum reality is to give up the notion of time—that the fundamental description of the universe must be timeless.”

No one has yet succeeded in using the Wheeler-DeWitt equation to integrate quantum theory with general relativity. Nevertheless, a sizable minority of physicists, Rovelli included, believe that any successful merger of the two great masterpieces of 20th-century physics will inevitably describe a universe in which, ultimately, there is no time.

The possibility that time may not exist is known among physicists as the “problem of time.” It may be the biggest, but it is far from the only temporal conundrum. Vying for second place is this strange fact: The laws of physics don’t explain why time always points to the future. All the laws—whether Newton’s, Einstein’s, or the quirky quantum rules—would work equally well if time ran backward. As far as we can tell, though, time is a one-way process; it never reverses, even though no laws restrict it.

“It’s quite mysterious why we have such an obvious arrow of time,” says Seth Lloyd, a quantum mechanical engineer at MIT. (When I ask him what time it is, he answers, “Beats me. Are we done?”) “The usual explanation of this is that in order to specify what happens to a system, you not only have to specify the physical laws, but you have to specify some initial or final condition.”

The mother of all initial conditions, Lloyd says, was the Big Bang. Physicists believe that the universe started as a very simple, extremely compact ball of energy. Although the laws of physics themselves don’t provide for an arrow of time, the ongoing expansion of the universe does. As the universe expands, it becomes ever more complex and disorderly. The growing disorder—physicists call it an increase in entropy—is driven by the expansion of the universe, which may be the origin of what we think of as the ceaseless forward march of time.

Time, in this view, is not something that exists apart from the universe. There is no clock ticking outside the cosmos. Most of us tend to think of time the way Newton did: “Absolute, true and mathematical time, of itself, and from its own nature, flows equably, without regard to anything external.” But as Einstein proved, time is part of the fabric of the universe. Contrary to what Newton believed, our ordinary clocks don’t measure something that’s independent of the universe. In fact, says Lloyd, clocks don’t really measure time at all.

“I recently went to the National Institute of Standards and Technology in Boulder,” says Lloyd. (NIST is the government lab that houses the atomic clock that standardizes time for the nation.) “I said something like, ‘Your clocks measure time very accurately.’ They told me, ‘Our clocks do not measure time.’ I thought, Wow, that’s very humble of these guys. But they said, ‘No, time is defined to be what our clocks measure.’ Which is true. They define the time standards for the globe: Time is defined by the number of clicks of their clocks.”

Rovelli, the advocate of a timeless universe, says the NIST timekeepers have it right. Moreover, their point of view is consistent with the Wheeler-DeWitt equation. “We never really see time,” he says. “We see only clocks. If you say this object moves, what you really mean is that this object is here when the hand of your clock is here, and so on. We say we measure time with clocks, but we see only the hands of the clocks, not time itself. And the hands of a clock are a physical variable like any other. So in a sense we cheat because what we really observe are physical variables as a function of other physical variables, but we represent that as if everything is evolving in time.

“What happens with the Wheeler-DeWitt equation is that we have to stop playing this game. Instead of introducing this fictitious variable—time, which itself is not observable—we should just describe how the variables are related to one another. The question is, Is time a fundamental property of reality or just the macroscopic appearance of things? I would say it’s only a macroscopic effect. It’s something that emerges only for big things.”

By “big things,” Rovelli means anything that exists much above the mysterious Planck scale. As of now there is no physical theory that completely describes what the universe is like below the Planck scale. One possibility is that if physicists ever manage to unify quantum theory and general relativity, space and time will be described by some modified version of quantum mechanics. In such a theory, space and time would no longer be smooth and continuous. Rather, they would consist of discrete fragments—quanta, in the argot of physics—just as light is composed of individual bundles of energy called photons. These would be the building blocks of space and time. It’s not easy to imagine space and time being made of something else. Where would the components of space and time exist, if not in space and time?

As Rovelli explains it, in quantum mechanics all particles of matter and energy can also be described as waves. And waves have an unusual property: An infinite number of them can exist in the same location. If time and space are one day shown to consist of quanta, the quanta could all exist piled together in a single dimensionless point. “Space and time in some sense melt in this picture,” says Rovelli. “There is no space anymore. There are just quanta kind of living on top of one another without being immersed in a space.”

Rovelli has been working with one of the world’s leading mathematicians, Alain Connes of the College of France in Paris, on this notion. Together they have developed a framework to show how the thing we experience as time might emerge from a more fundamental, timeless reality. As Rovelli describes it, “Time may be an approximate concept that emerges at large scales—a bit like the concept of ‘surface of the water,’ which makes sense macroscopically but which loses a precise sense at the level of the atoms.”

Realizing that his explanation may only be deepening the mystery of time, Rovelli says that much of the knowledge that we now take for granted was once considered equally perplexing. “I realize that the picture is not intuitive. But this is what fundamental physics is about: finding new ways of thinking about the world and proposing them and seeing if they work. I think that when Galileo said that the Earth was spinning crazily around, it was utterly incomprehensible in the same manner. Space for Copernicus was not the same as space for Newton, and space for Newton was not the same as space for Einstein. We always learn a little bit more.”

Einstein, for one, found solace in his revolutionary sense of time. In March 1955, when his lifelong friend Michele Besso died, he wrote a letter consoling Besso’s family: “Now he has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.”

Rovelli senses another temporal breakthrough just around the corner. “Einstein’s 1905 paper came out and suddenly changed people’s thinking about space-time. We’re again in the middle of something like that,” he says. When the dust settles, time—whatever it may be—could turn out to be even stranger and more illusory than even Einstein could imagine.